Regulating device for refrigerating apparatus



Sept; 20, 1938. J. KIRGAN 2,130,549

REGULATING DEVICE FOR REFRIGERATING APPARATUS Filed March 25, 1956'INKENTOR. tlahn/ lfu'jan.

HIS ATTORNEY Patentedsept. 20, 1938 v PATENT OFFICE 2,130,549 v anoomrmoDEVICE FOR gEFRIGERATlNG APPARA John Kirgan, Easton, Pa, assignor toIngersoll- Rand Company, Jersey City, N. J., a corpora- I tion of NewJersey Application March 25, 1936, Serial No. 70,749

12 Claims.

My invention relates to refrigerating apparatus, and especially to aregulating device to facilitate and ensure the continuous and normaloperation of same.

An object of the invention is to provide novel means for limiting theminimum temperature to be imparted to a liquid refrigerant and thusprevent solidification or freezing thereof.

The invention is particularly adapted for use with a refrigeratingsystem in which a liquid refrigerant is cooled in a high vacuum byvaporization of part thereof. In such a system the refrigerating efiectdepends on uninterrupted circulation and if freezing should occuroperation would 15 be suspended.

Systems of the kind mentioned include an evaporator to receive therefrigerant, an evacuator for the removal of vapor therein and acondenser in which the vapor is liquefied. By means of a suitableexhaust device the pressure in the condenser is made to sustain at adefinite relation to the required low pressure in the evaporator topermit vaporization to proceed. If the pressure in the condenser becomestoo great, the pressure in the evaporator reaches too high a figure andvaporization is checked until pressure in the condenser again drops to aprescribed level. Hence by causing the pressure in the condenser to riseat a predetermined moment, further cooling can be stopped and freezingof the system is averted.

Another object of the invention is to provide an apparatus by which therisk of freezing of the liquid refrigerant is eliminated through theoperation of the exhausting unit for bringing about the necessary lowpressure in the condenser so that at'the required moment the pressure inthe condenser is caused to increase and the rate of vaporization is thendiminished until normal conditions are again obtained.

40 An additional object of the invention is to provide a connectionbetween the chilled liquid refrigerant leaving the evaporatorand thepower medium for actuating the exhaust device of the condenser such thatthe power medium is regulated in response to the falling temperature ofthe refrigerant to give the desired result.

. In its preferred form the invention comprises an evacuator ofcentrifugal design driven by a turbine, and the discharge of bothmachines is transferred to condensers that are traversed by to reducethe amount of power fluid therefor when the refrigerant is cooled too.much. This reduction causes a rise in the pressure of the condensercoupled to the compressor which is immediately followed by a reductionin the output of the com- '5 pressor and a reduction in the amount ofvapor removed from the evaporator. The amount of vapor generated thendecreases and the pressure and temperature are prevented from fallingbelow the danger point. 10,

Other objects and advantages of the-invention will be fully apparent inthe ensuing description and accompanying drawing; and while but oneembodiment is shown I reserve the right to make changes in the shape,size and arrangement of 15 the various parts within the scope andprinciple of the invention.

On the drawing the figure is a side viewiiartly in section showing aconstruction according to this invention. 20

The numeral I indicates an enclosed vessel called an evaporator which isexhausted of vapor created therein by means of an evacuator having theform of a centrifugal compressor 2. The a liquid refrigerant to becooled is introduced into 25 the evaporator through a header 3 havingopenings through whichthe refrigerant is expelled in the form of jets.or sprays. The compressor 2 communicates with the inside of theevaporator through a port 4 and maintains a sufficient -vac- 3o uum inthe evaporator to cause some of the re: frigerant to be vaporized atonce, and heat is thus taken out of the main body of the refrigerant sothat the bulk of the refrigerant which remains liquid is chilled. Itpasses out through a 35 pipe 5 and is conducted to a place where therefrigerating effect is desired. After being warmed by absorbing heatthereat it returns to the evaporator through the header 3 and is cooledover. The compressor 2 is rotated by a turbine 6 that 40 is operated bysteam supplied through a pipe 1 and this turbine may be coupled to thecompressor through any suitable gearing shown at 8.

The compressor or blower delivers the vapor that it takes out of theevaporator to a condenser 9, while the steam consumed in the turbine isdischarged into a condenser l0 through an outlet flue II. The condenser9 receives water or other cooling medium through a pipe 12, and thewater flows out of this condenser through a pipe l3 into the othercondenser l0 and leaves the other condenser by way of a pipe ll. Thetemperature of the condenser l0 and its internal pressure are thereforeslightly higher than the temperatureand pressure in the condenser 9. I

To obtain the proper pressure in the condenser 9 below the atmospherethis condenser is connected to a steam ejector comprising a casing l5which connects with the outlet pipe ll of the turbine. This casingcommunicates at its other end with the interior of the condenser 9 andit has an inside nozzle I6 connected to a steam pipe ll, the latterhaving a regulating valve H in a fitting l9 therein.

So long as the valve I8 is fully opened the pressure in the condenser 9will be kept low enough to permit the compressor to continue evacuatingvapor from the evaporator I, but if the water passing out through thepipe 5 should ever become too cold the valve I8 will partly close by theaction of athermostatcomprising a bulb 20 in the pipe 5 and connected bya tube 2i to means to operate this valve. Both the bulb and the tube arefilled witha thermally responsive liquid.

To enable this thermostatic element to move the valve the tube 2| islead to an expansible' casing 22 which is in operative relation with theouter end of the stem 23 of the valve l8. This stem has a head 24 on itand is encircled by a spring 25'which normally tends to close, thevalve. The end of the casing 22 to which the tube 2| is attached isfixed, but the other end is movable and is engaged by'the spring 25between it and the fitting l9. So long as the bulb 20 does not becometoo cool the pressure in the casing 22 will hold the valve l8 fullyopen, but this valve will move toward closed position when the thermallyresponsive fluid in the bulb and tube contracts. The condenser In forthe turbine is pumped out by any suitable appliance, not shown herein.

In operation the water temperature will at most times be high enough tokeep the valve l8 open against the spring 25, and the ejector l6 willthen maintain a sufiiciently low pressure in the condenser 9 to ensuresatisfactory operationthereof. The water entering through the header 3will be chilled, forced out through the conduit 5 to be warmed and thenreturned to be chilled again. I

If, however, the temperature of the chilled water passing out throughthe pipe 5 approaches the freezing point the contraction of the liquidin the bulb 20 and tube 2| will, at say 35 F., allow the spring 25 tocompress the casing 22 and move the valve l8 toward closed positionthereby cutting down the steam supplied to the ejectorl6. The

capacity of the booster will be thus diminished and the temperature andpressure in the condenser will increase and approach the temperature andpressure prevailing inside the other condenser It). When this occurs therate of liquefaction of vapor in the condenser 9'will decrease due inpart to the slower removal of gases by the ejector l6 and in part to theslower delivery of vapor by the compressor 2. The slower deliveryofvapor will in turn cause a decrease in the rate of vaporization and anincrease in pressure in the evaporator G.

The rate of vaporization in the evaporator will also be greatlyinfluenced by the variable compression characteristic of the compressor2, for, when the back pressure on the compressor is increased the ratioof compression of the compressor will likewise increase. The increase ofcompression-ratio will be accompanied by a decrease in capacity and thiswill in turn be manifested by a further increase of evaporator pressureand temperature and a further decrease in the rate of vaporization. Lessheat will then be extracted from the water entering the evaporator andthe temperature of the chilled water will be prevented from fallingbelow the predetermined minimum. As soon as the temperature of thechilled water again exceeds the said minimum normal operation of ejectorIE will be resumed. Hence, it is seen that the decrease in the rate ofvaporization is a direct result of the decrease in the rate ofliquefaction and the increase of pressure in condenser 9.

' Other methods of decreasing the rate of liquefaction and increasingthe pressure in the condenser, such as'increasing the temperature of theincoming condenser cooling water, will be apparent to those skilled inthe art. I, therefore, do not wish to be limited by the specificembodiment shown, but desire that the scope of the invention bedetermined by the claims hereinafter appended. v

I claim:

1. The combination of a source of gaseous or vaporous fluid, acompressor for removing fluid from the source, means for energizing thecompressor, a condenser to which the compressor discharges, an ejectorfor exhausting the condenser, a condenser to which the ejectordischarges, and means to vary the operation of the ejector in accordancewith variations of the temperature in said source whereby under certain.temperature conditions the pressure in the first condenser approachesthe pressure in the second condenser to limit the output of thecompressor.

2. The combination of a source of gaseous or vaporous fluid, acompressor for removing fluid from the source, means for energizing thecompressor, condenser means to which the compressor discharges, anevacuator for exhausting the condenser, condenser means to which theevacuator discharges, means to pass cooling medium serially through thefirst and second said condenser means, the second said condenser meansthereby operating under higher conditions of temperature and pressurethan the first said condenser means, and means to vary the operation ofthe evacuator in accordance with variations of the temperature in saidsource to enable the pressure in the first said condenser means toapproach the pressure in the second said condenser means to limit theoutput of the compressor.

3. The combination of a source of gaseous or vaporous fluid, acentrifugal compressor for removing fluid from the source. a turbine fordriving the compressor, a' condenser to which the compressor discharges,a condenser to which the turbine discharges, a connection communicating"between the condensers, means for impelling uncondensed gases from thefirst condenser through said connection to the second condenser, and adevice for regulating said means whereby under certain conditions theflow through said connection may be reversed to increase the pressure inthe first condenser andthereby decrease the output of the compressor.

4. The combination of a source of gaseous or vaporous fluid, acentrifugal compressor for removing fiuid from the source,-a turbine fordriving the compressor, separate condensers for receiving the dischargesof the compressor and turbine, a conduit connecting the condensers,means for impelling uncondensed gases from the compressor condenserthrough the conduit to the turbine condenser, and a device acting inaccordance with conditions at said source to control the operation ofsaid means whereby under certain conditions the fiow through saidconduit may be reversed to' augment the pressure in the comvapor,exhausting uncondensed gases from the vapor as the vapor condenses, andvarying the amount of uncondensed gases exhausted in accordance withvariations of the temperature in the source of vapor to thereby vary theamount of vapor compressed and condensed.

6. The method of compressing vapor which consists in removing vapor fromits source, compressing the vapor, subjecting the compressed vapor tocondensing action, separating and removing uncondensed gases from thevapor as it condenses thereby to maintain low condensing pressure and alow ratio of compression, and vary-v ing the rate oi removal of theuncondensed gases in response to the temperature at the source of vaporin order to vary the condensing pressure and the ratio of compressionfor maintainin such temperature above a certain minimum.

7. The combination of a vessel containing gas or vapor, a compressor toreduce the pressure in the vessel, means to energize the compressor,condenser means to which the compressor discharges, means for exhaustingthe condenser to reduce the pressure therein, means to supply powermedium to the exhausting means, and a temperature responsive deviceactuated by the temperature in said source to vary the supply of powermedium to the pump in accordance with variations of the temperature insaid source whereby the operation of the pump is regulated to controlthe pressure in the condenser and the amount of fluid discharged by thecompressor.

8. The combination of an enclosed vessel containing gas or vapor, acompressor to reduce the pressure in the vessel, a turbine for drivingthe compressor, a condenser to which the compressor discharges, acondenser to which the turbine discharges, an evacuator to reduce thepressure in the first said condenser and discharging into the secondsaid condenser, means to supplyv power medium to the evacuator, andmeans acting in response to the temperature in the vessel to control thelast said means and the operation of the evacuator and acting as thetemperature falls in the vessel to cause the pressure in the first saidcondenser to approach the pressure in the second said condenser forcontrolling the output of the compressor and the pressure and temperature in the vessel.

9. The combination of a source of gaseous or vaporous fluid, acompressor for removing fluid from the source, a condenser to which thecompressor delivers} a device for exhausting said condenser, means'forsupplying power medium to the device, and a temperature responsivedevice actuated by the temperature in said source to vary the supply ofpower medium to the pump in accordance with variationsin temperature ofsaid source whereby the operation of the pump is regulated to controlthe pressure in the condenser and the amount of fluid discharged by thecompressor.

10. The combination of a source 01' gaseous or vaporous fluid, acentrifugal compressor for evacuating said source, a condenser intowhich the compressor discharges, a steam ejector to exhaust thecondenser and reduce its pressure, means to supply steam to the ejector,and means controlled by the temperature of the contents of said sourceand acting to regulate said steam supply to thereby determine thecondenser pressure and the rate of discharge of the compressor.

11. The combination of a source of gaseous or r vaporous fluid, acentrifugal compressor for evacuating said source,.a power unit tooperate the compressor, a condenser into which the compressordischarges, a second condenser, a pipe through which said unitdischarges into the second condenser, an exhauster for the firstcondenser connected to said pipe, and means controlled by the contentsof said source and acting to regulate the operation of said exhausterwhereby under certain conditions of the source the pressure in the firstcondenser approaches the pressure in the second condenser to limit theoutput of the compressor.

v 12. The combination of a source of gaseous or vaporous fluid, acompressor for removing fluid from the son e, means for energizing thecompressor, a con epser'to which the compressor discharges, meansforexhausting the condenser, and temperature responsive means'actuatedby the temperature in said source to regulate and vary operation of theexhausting means in accordance with variations of the temperature insaid source whereby the pressure in the condenser is regulated tocontrol the output 01' the compressor.-

, JOHN KIRJGAN.

